Commutator brush



Dec. 14, 1937. c ARNOLD 2,102,347

COMMUTATOR BRUSH Filed June 29, 1936 Ema/whom Jwvzzs 67/42/1040 3%fiQwmz w.

ratented Dec. 14, 1937 COMMUTATOR BRUSH James 0. Arnold, Los Angelea,Calm, assignmto Lane-Wells Company, Los

Angeles, Calif., a

corporation of Delaware Application June 29, 1936, Serial No. 87,965 8Claims. (Cl. 171-323) This invention relates to commutator brushes.Commutators are often utilized in conjunction with recording instrumentsand apparatus designed to measure the electrical characteristics 6 oftwo or more circuits either to obtain an average thereof or to compare.Also, commutators are incorporated in instruments which measure a singlecircuit under different conditions as when the polarity is reversed orthe phase relation is changed. For example, in the electricalprospecting of well bores by certain methods, two circuits are utilizedand the measuring instrument is interposed alternatingly therein.

It is often mandatory in conjunction with commutators so employed toinsure that the making and breaking of contacts with the circuitsassociated therewith are exactly simultaneous, particularly where thepower in such circuits is low, in order that there be no fluctuation inthe measuring device occasioned by such making or breaking of contactwhich would interfere with the variable being measured.

Accordingly, the objects of this invention are:

First, to provide a commutator brush comprising dual brush elementswhich delineate its axially extending margins.

Second, to provide a commutator brush wherein such brush elements may beindependently adjusted arcuately to change the eflective width 0 of saidbrush as well as the position as a whole of the commutator brush.

Third, to provide a commutator brush which, when several are positionedabout a commutator, is particularly arranged to permit adjustment of 35each commutator brush with respect to the others so that the making andbreaking of the several commutator brushes may occur simultaneously.

Fourth, to provide a commutator brush which incorporates a novellyconstructed brush element 40 having a thin line contact only with thecommutator so.that the point of contact is accurately defined.

Fifth, to provide, on the whole, a commutator brush of this class whichis simple of operation 45 and adjustment, easily installed andincorporated with conventional commutator arrangements, and which doesnot readily deteriorate or get out of order.

With the above and other objects in view as 50 may appear hereinafter,reference is made to the accompanying drawing, in which:

Fig. 1 is an elevational view of a commutator and drive thereforincorporating my commutator brush.

65 Fig. 2 is an enlarged transverse sectional view through 2--2 of Fig.1 showing several of the commutator brush units in engagement with thecommutator.

Fig. 3 is an end elevational view of one of the commutator units takenthrough 3-4 of Fig. 2. 5 Fig. 4 is a sectional view thereof takenthrough 4-4 of Fig. 2.

In the accompanying drawing, my commutator brush is shown in conjunctionwith a motor driven commutator such as employed in con- 10 junction withwell bore surveying apparatus. A base I is provided, at one end of whichis mounted a motor 2 which turns a drive shaft 3 extending throughbearings provided in upstanding bracket plates 4 between which ismounted a commutator l5 5. The commutator 5 is shown as comprisingsubstantially semicircular conductor segments I electrically connectedto conductor rings 1 and separated by suitable insulation 8. The bracketplates 4 are connected by four brush supporting 0 bars 9 which parallelthe commutator and are positioned equally around the commutator.

The bars 9 serve to support a plurality of commutator brush units ll.Each brush unit which rides upon the conductor segments 8 includes an 25eccentric bushing i2 of insulating material which is mounted upon one ofthe bars 8 and is adapted to be secured thereto by a set screw II. Theeccentric bushing is provided with Journaled bosses l4 at each end uponwhich ride a pair of side plates l5 forming a part of a brush arm Hi.The side plate extends either over or under the commutator, dependingupon the bar with which it is associated. These plates are connected bya cross piece I! near their extended ends. Each cross piece receives abrush element ll. Each brush element is in the form of a flat strip ofconducting material forming a supported end l9 which lies flat againstthe corresponding 40 cross piece and contact fingers 20 formed by makingparallel slits inwardly from the extended end, as shown best in Fig. 3.

The contact fingers may extend directly from the supported end at anangle therewith or an oflset 2| may be interposed, as shown best in Fig.2; the purpose being to position the contact fingers in the rightrelation with the commutator. Each brush element is held in place by ascrew 22. One screw sufiices by reason of the fact that the side platesl5 project past the cross piece 20 and restrain the brush elementagainst turning.

The commutator brush units H are arranged in pairs with the extendedends of the members of each pair disposed contiguously to each other. Inorder to electrically connect the members of each pair of commutatorbrush units and to urge their brush elements against the commutator, thecross pieces it are provided with outwardly extending pins 23, and thepins of each pair are connected by springs 22d.

in addition to the commutator brush units it which ride on the segmentalportions of the commutator, othe" brush units 25 provided which ride reconductor rings '8. These brush units may be conventional or may beconstructed along the lines of the brush units it. In the latter case,the insulating bushings need not be made eccentric, and only one unitneed engage the ring.

Operation of this commutator brush arrangement is as follows:

Each pair of brush units forms in effect a single commutator brushstructure; one of the brush elements indicated by M. making contact withthe several segments, and the other brush element designated 33 breakingcontact therewith. It is essential that the brush elements M of the twobrush structures engage their respective segments in as closesynchronisin as possible and that the brush elements it break contactwith these segments in synchronisrn. By adjusting the positions oi theeccentric bushings on their bars the efiective width oi brush structuremay be varied, or the brush structure as a whole anew/ed. arcuately oneor anoth r with respect to the other brash structure in order that themost perfect adjustment may be obtained. Each brush element is made asthin as possible in order to make a fine lineal contact with thecommutator so that the effective edge of the brush struc e is accuratelydefined.

lfiiough have shown and described a par ticular embodiment of thisinvention, I do not wlshto be limited thereto but desire to in'corporate in the scope or my invention the constructions, combinations, andarrangements embraced in the appended claim:

1. A commutator brush struotin'e comprising: pair of brush elementsdisposed in contiguous relation with each other and engageable with acommutator; means electrically coupling said brush elements directly onewith the other so that they form in effect a single brush means; and adevice for shifting said to and in each other to vary the effectiveWidth of relati o the enact-iv 3. A commutator brush structurecomprising: a pairof brush elements electrically connected with eachother and together constituting a brush means, one of said brushelements engageable with a commutator to make contact with the segmentsthereof and the other similarly engageable to break contact with saidsegments; and means for adjusting said brush elements to vary theefiective width of said brush means.

4. A commutator brush structure comprising: a pair of brush elementseach arranged to make a lineal contact with a segmented commutator, saidbrush elements being electrically connected to define contact making andbreaking edges of a common brush means; and a. device for shifting saidbrush elements to vary the eifective width of said brush means and theposition thereof with respect to said commutator.

5. A commutator brush structure comprising: a pair of brush elementselectrically connected to form a single brush means; and a device forrelatively adjusting said brush elements to vary the effective Width ofsaid brush means, said device including holders for said brush elements,eccentric bushings for said holders, and journals for said bushings.

6. A commutator brush structure comprising: a. pair of brush elementseach arranged to make a lineal contact with a segmented commutator, saidbrush elements being electrically connected to define contact making andbreaking edges of a common brush means; and a device for shifting saidbrush elements to vary the effective Width of said brush means and theposition thereof with respect to said commutator, said device includingholders for said brush elements, eccentric bushings for said holders,and journals for said bushings.

7. The combination with a commutator and supporting means extendingtherealong: a brush holder bushing eccentrically mounted on saidsupporting means; a brush holder journaled on said bushing; and a brushelement of sheet material carried by said brush holder and engaging saidcommutator edgewise to make a lineal contact therewith.

8. The combination with a commutator and supporting means extendingtherealong: a brush holder bushing eccentrically mounted on saidsupporting means; a brush holder journaled on said bushing; and a brushelement of sheet material carried by said brush holder and engaging saidcommutator edgewise to make a lineal contact therewith, the contactingportion of said brush comprising a plurality of alined yieldable fingersextending axially along said commutator.

JAMES C. ARNOLD.

